High survival and growth of European lobster juveniles (Homarus gammarus) reared communally on a natural-bottom substrate

Abstract

A series of communal rearing experiments with European lobster (Homarus gammarus) performed in 1998 and 1999 at the Kvitsøy Lobster Hatchery in Norway tested methods for future production of juveniles for farming and release purposes. Lobster larvae were raised from stage IV in tanks or cages with a bottom substrate of shell sand and a variety of shelters. Survival rates after 4 to 5 months ranged from 10 to 67%; averages were 59% in 1998 and 30% in 1999. Final densities ranged from 29 to a maximum of 130 juvenilesm–2 ; means were 72 in 1998 and 55 in 1999. As expected, the fastest growth was found in tanks with heated water (15–19˚C), where mean carapace length (CL) was 17 mm after 4 months, compared to a mean CL of 11 mm in unheated water. Size at the end of the experiments was highly variable, even within the offspring from a single family, and especially in heated water. Lobsters raised communally were in general larger and more variable than were lobsters raised in single compartments.